Thanks, folks! I did the install this morning and it went well. I went a little overboard and used a total of 7 sleeve anchors, so that thing isn't going anywhere. The chimney will fall down first. I put liquid nails on two of the top ones and two on the bottom.

The sleeve anchors were a pretty big pain to deal with. Maybe I didn't have the embedment depth correct. Or I might have done things in a bit of an incorrect order.

Fortunately, the mount lined up nearly perfectly along two mortar lines. I've always gone into the mortar before but was starting to doubt myself once I saw a ton of debate online. I've gone into brick too when necessary, but agree with your assessments that it's easy to chip/blowout and hard to drill through. The mortar cuts like butter with a halfway decent bit.

I've attached shots of the job.